zram: fix pool name truncation
zram_meta_alloc() constructs a pool name for zs_create_pool() call as
snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);
However, it defines pool name buffer to be only 8 bytes long (minus
trailing zero), which means that we can have only 1000 pool names: zram0
-- zram999.
With CONFIG_ZSMALLOC_STAT enabled an attempt to create a device zram1000
can fail if device zram100 already exists, because snprintf() will
truncate new pool name to zram100 and pass it debugfs_create_dir(),
causing:
debugfs dir <zram100> creation failed
zram: Error creating memory pool
... and so on.
Fix it by passing zram->disk->disk_name to zram_meta_alloc() instead of
divice_id. We construct zram%d name earlier and keep it as a ->disk_name,
no need to snprintf() it again.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index fb655e8..763301c 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -496,10 +496,9 @@
kfree(meta);
}
-static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize)
+static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
{
size_t num_pages;
- char pool_name[8];
struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
if (!meta)
@@ -512,7 +511,6 @@
goto out_error;
}
- snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);
meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM);
if (!meta->mem_pool) {
pr_err("Error creating memory pool\n");
@@ -1031,7 +1029,7 @@
return -EINVAL;
disksize = PAGE_ALIGN(disksize);
- meta = zram_meta_alloc(zram->disk->first_minor, disksize);
+ meta = zram_meta_alloc(zram->disk->disk_name, disksize);
if (!meta)
return -ENOMEM;
